JOAO COUTINHO FERREIRA

JOAO COUTINHO FERREIRA

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Calcium determination by permanganometry and EDTA complexation
2024 - SANTOS, DANIELA da C.G.; NASCIMENTO, LETICIA da S.; BUSTILLOS, JOSE O.W.V.; COUTINHO, JOAO F.; BERGAMASCHI, VANDERLEI S.; OTOMO, JULIANA I.
Purification of lithium hydroxide by ion-exchange processes for application in nuclear reactors
2021 - GIMENEZ, MAISE P.; OTOMO, JULIANA I.; FERREIRA, JOAO C.; BERGAMASCHI, VANDERLEI; BUSTILLOS, OSCAR V.
Applications of lithium in nuclear energy
2017 - OLIVEIRA, GLAUCIA A.C. de; BUSTILLOS, JOSE O.V.; FERREIRA, JOAO C.; BERGAMASCHI, VANDERLEI S.; MORAES, RAFAELI M. de; GIMENEZ, MAISE P.; MIYAMOTO, FLAVIA K.; SENEDA, JOSE A.
Lithium is a material of great interest in the world, it is found in different minerals on Earth's crust (spodumene, lepidolite, amblygonite and petalite) also in salt pans. This element belongs to alkaline group and has two natural isotopes: Li-6 and Li-7. In the nuclear field, lithium isotopes are used for different purposes. The Li-6 is applied in the production of energy, because its section of shock is larger than the other isotope. The Li-7 regulates the pH in refrigerant material in the primary circuits of the Pressurized Water Nuclear Reactor (PWR). In nuclear reactor, lithium is used as a heat transfer due its boiling temperature (1342°C), making it an excellent thermal conductor. However, to reach all these applications, lithium must have high purity (> 99%). The main processes to reach a high purity level of lithium employee a combination of solvent extraction and ion exchange process, to obtain its salts or ending with chemical electrolysis of its chlorides to obtain its pure metal. This work presents a review of new applications of Lithium in Nuclear Energy and its purification and enrichment processes.
Recovery of thorium and rare earth elements from sludge with the aid of anionic exchanger
2006 - ABRAO, ALCIDIO; FERREIRA, JOAO C.; SALVADOR, VERA L.R.; ZINI, JOSIANE; CARVALHO, FATIMA M.S. de
Abstract During operation of a solvent extraction pilot plant for preparation of pure thorium nitrate, a thorium concentrate produced industrially from monazite processing in São Paulo containing the REE as main impurities and some minor elements like iron, titanium, lead, sodium and silica was dissolved with hot nitric acid following by digestion and addition of flocculants was filtered for the separation of some insoluble fraction. Thorium was extracted with TBP-diluent in a pulsed column. Small amount of this thorium nitrate was used for nuclear research and the gross production was supplied to some companies that manufacture thorium gas light mantle in Brazil. The raffinate still containing some thorium and the totality of REE was treated with sodium hydroxide and the hydroxides as sludge are stocked. Nowadays there is a stockpile of circa 25 ton of the mentioned material. In this work it is reported a process for separation of thorium from rare earth elements (REE) and their recovery from this accumulated sludge. It is dissolved with hot nitric acid, filtered to separate any insoluble and an excess of acid is added. The prepared solution is fed into a strong anion ion exchanger previously treated with 1mol L-1 HNO3. Thorium nitrate as an anionic complex is retained while REE and other impurities are passed to the effluent. This effluent is treated to obtain a rare earth concentrate for future work of individual separation of the elements. The resin could retain only very small amounts of cerium and lanthanum, but both are excluded when the column is saturated with thorium. Thorium nitrate is eluted with diluted nitric acid. The process is operationally simple and was developed and successfully performed keeping in mind a future installation for the recovery of thorium and rare earths from the above mentioned sludge.